The most common way of measuring the volume of fuel in a fuel tank of a motor vehicle consists in using a variable printed resistor card associated with a floating arm inside the fuel tank. The main disadvantage of this technology is sensitivity to contamination and chemical attack. Recent evolutions in fuels (lower sulphur rates), have forced manufacturers to use noble metal on the resistor cards (Pd, Pt and Gold instead of Silver/Ni). Other technologies can overcome these difficulties, so-called contact-less (ultrasonic, capacitive, magnetic, inductive) sensors, but these all require the sensor to be immersed in the fuel in the fuel tank.
The aim of the present invention is to overcome the above-mentioned problems.